As broadband networks develop rapidly, video communication systems, especially multipoint conferencing systems, are gaining increasing popularity today. Government agencies, military sectors, public security departments, and businesses are building or expanding their conferencing systems. With the development of video communication technologies and the capacity expansion of video communication systems, a media control server (for example, a multipoint control unit (MCU)) is often cascaded in networking.
In earlier cascade networking, one cascaded channel is available between any two cascaded MCUs, and the cascaded channel can be used to transmit one channel of media signals. For example, one cascaded channel is available between MCU1 and MCU2, terminals T1 and T2 are connected to ports of MCU1; MCU1 could transmit only one channel of video/audio signals of T1 or T2 to the cascaded MCU2, so that a terminal connected to MCU2 can establish video communication with T1 or T2 at the same time. Therefore, such single-channel based cascading cannot be used to implement services such as TV wall and continuous presence, thereby limiting the applications of a multipoint conferencing system. After the multichannel cascade technology emerges, at least two cascaded channels can be established between any two cascaded MCUs. In this way, multiple channels of media signals can be transmitted between the MCUs to implement services such as TV wall and continuous presence.
However, the inventor finds that in the existing multichannel cascade networking structure, there is one-to-one mapping between channels and terminals. If there are many terminals, more cascaded channels are required. In particular, in case of complex cascading, every time an MCU is cascaded, more cascaded channels will be established between any two MCUs. As a result, a huge number of cascaded channels occupy very high bandwidth, thereby wasting considerable bandwidth resources.